1. Field of the Invention:
This invention relates in general to subsea wells and in particular to a connector for connecting a tieback conductor to a wellhead.
2. Description of the Prior Art:
The purpose of a tieback of a conductor string from a fixed platform to a previously drilled well is to achieve a structural connection between the well and platform that will resist internal pressure as well as externally applied axial, lateral and bending forces. A rigid connection between the conductor string and the wellhead is considered to be superior to a non-rigid type connection.
In U.S. Pat. No. 4,343,495, Philippe C. Nobileau et al, Aug. 10, 1982, and in U.S. Pat. No. 4,696,493, Norman Brammer, Sep. 29, 1987, the tieback systems utilize an internal bushing to provide a preloading contact between horizontal surfaces of the wellhead and the tieback connector. The connector utilizes a guide funnel for initial stabbing. Bearing surfaces in the funnel operate on the outside surface of the wellhead to force the conductor string into angular alignment with the wellhead under the influence of the weight of the conductor string. Seals located between the tieback connector and the wellhead are compressed with axial movement of the tieback connector. Then, the lock bushing is operated to clamp the connector to the wellhead.